Many different types of so-called child resistant or safety closure members are known which are intended to close the open ends of containers in a manner so as to render it difficult for a child to remove the closure member to obtain access to the contents of the container. As examples of known closure members of this type, reference is made to U.S. Pat. Nos. 3,860,137 and 3,964,634.
Known safety closure members generally fall into one of several categories. One category is constituted by closure members which include locking protuberances or the like which cooperate with locking recesses or grooves formed on the neck of the container. Some of these closure members are characterized in that in order to remove them from the container, it is necessary to rotate the closure member relative to the container neck until the locking protuberance and associated recess in which it is received are no longer engaged thereby permitting the closure member to be removed from the container. Another category of child-resistant closure member is constituted by closure members characterized by a top and a depending peripheral threaded skirt and which are adapted to be threadedly fastened onto the neck of the container. In one well known closure member of this type, a threaded cylindrical insert is provided within the closure member which will not rotate with rotation of the closure member unless a substantial axial force is exerted on the top of the closure member simultaneously with the rotation thereof.
Problems have been encountered with various ones of the presently known closure members. Generally, existing child-resistant closure members are often designed in a manner such that not only is a child prevented from obtaining access to the contents of the container but it is not uncommon for adults to encounter difficulties in removing the closure members from the container. For example, elderly or debilitated people often have trouble in accurately rotating the closure member with respect to the container neck to disengage the locking protuberance and recess in the case of the first category of closure members discussed above. In the case of the second category of closure members identified above, it is not uncommon for even a healthy person to have difficulty in rotating the threaded insert situated within the closure member to obtain access to the contents of the container. This may be due to the inability of the person to exert sufficient force to rotate the threaded insert along with the closure member or may be the result of a failure of the closure member itself. Moreover, certain conventional child-resistant closure members are subject to being inadvertently opened and are generally relatively complicated in construction and expensive in manufacture.